An ejector type refrigerating cycle is proposed, for example as disclosed in Japanese Patent No. 3322263, in which an ejector is used as a means for depressurizing and circulating refrigerant in the refrigerating cycle of a gas compression type.
According to the above prior art (JP Pat. No. 3322263), as shown in FIG. 20, a first vaporizing device 61 is arranged between a refrigerant outlet side of an ejector 14 and a gas-liquid separator 63, and a second vaporizing device 62 is arranged between a refrigerant outlet side of the gas-liquid separator 63 and a refrigerant suction port 14b of the ejector 14.
In the above ejector type refrigerating cycle, a gas phase refrigerant discharged from the second vaporizing device 62 is sucked into the ejector 14 by pressure decrease caused by jet flow at expansion of the refrigerant, and speed energy is converted into pressure energy by a defusing portion (a pressure increasing portion) 14d to increase the refrigerant pressure. As a result, a driving force of a compressor 11 can be reduced, to improve operational efficiency of the cycle.
Heat absorbing operation (cooling operation) can be carried out by the two vaporizing devices 61 and 62 for independent two spaces or one common space.
It is further disclosed in the above prior art that, according to the ejector type refrigerating cycle, only one vaporizing device 62 is arranged between the refrigerant outlet side of the gas-liquid separator 63 and the refrigerant suction port 14b of the ejector 14, and an internal heat exchanger is provided to perform heat exchange between the gas phase low-pressure refrigerant flowing out from the gas-liquid separator 63 and the high-pressure refrigerant at an outlet side of a heat radiating device 13.
It is, however, a problem in the ejector type refrigerating cycle of the above prior art that flow amounts of the refrigerant to the respective (first and second) vaporizing devices 61 and 62 are not easily adjusted, because the respective flow amounts of the refrigerant to the first and second vaporizing devices 61 and 62 must be adjusted by the one ejector 14, whereas the operation (function) of the ejector 14 for circulating the refrigerant (suck-in operation of the gas phase refrigerant) is performed at the same time.
Furthermore, in a low load operation, in which a thermal load for the cycle is small, pressure difference between high-pressure side and low pressure side of the refrigerant in the cycle becomes smaller, and input energy of the refrigerant to the ejector is correspondingly small. As a consequence, the refrigerant suck-in performance is decreased at the ejector 14, the flow amount of the refrigerant passing through the second vaporizing device 62 is thereby decreased. This results in another problem that the performance for the cooling operation at the second vaporizing device 62 is decreased.
This problem also occurs in the ejector type refrigerating cycle having the internal heat exchanger, which is disclosed in the drawings 34 to 38 of the above prior art (JP Pat. No. 3322263).